The deleterious effects of tobacco abuse are well known and regulatory agencies as well as the public constantly react to these scientific and epidemiologic evidences. Tobacco is indeed a worldwide public health hazard accounting for significant morbidity and mortality. Although smoking places an abundant oxidant insult to the oro-pharynx and respiratory tract, plus the local existing atmospheric pollutants in that specific environ, evidence cites the oxidant burden is on the entire organism of the smoker, particularly development or enhancement of atherosclerosis, causing cardiovascular disease, chronic obstructive pulmonary disease and various forms of cancer, including carcinomas of the mouth, pharynx, esophagus and lung.
Tobacco is a substance consisting of the dried leaves and stems of the plant Nicotiana tabacum which contains the drug nicotine, which is very addictive. The plant is native to North America but is now grown worldwide. Tobacco abuse has been identified as the single most preventable cause of disease, morbidity and mortality. Tobacco smoke contains many toxic chemicals and free radical species. There are three principal ways to consume tobacco: smoking, chewing and dipping and snuffing. 50 million Americans smoke and countless others are affected by tobacco smoke as secondary smokers. Children of smokers breathe this second-hand smoke and have more respiratory problems than children of non-smokers. Smokeless tobacco is used by as many as 12 million individuals and has a detrimental effect on the oral cavity plus systemic effects from buccal absorption of nicotine and other chemicals. Chewing looseleaf tobacco and "dipping" moist, ground snuff tobacco are common uses of tobacco without smoking. "Snuffing," that is, "snorting" dry powdered tobacco into the nasal passageways is rarely used in this country. Health risks from smokeless tobacco are still very significant and it is not a substitute for smoking.
Studies have estimated that tobacco smoke has over 3,000 different constituents, of which a number are toxic, some are carcinogenic and many generate free radical species. Most of these compounds have been identified in so-called mainstream and side stream tobacco smoke. The former is that volume of smoke drawn through the mouthpiece of the tobacco product during puffing while side stream smoke is that smoke emitted from the smoldering cigarette in between puffs. Although tar and nicotine are retained in the filter of cigarettes, this applies mainly to mainstream smoke, when comparing filter and non-filter cigarettes. Mainstream smoke emission is also markedly reduced both in low and in ultra low tar yield cigarettes. However, the emissions of toxic and carcinogenic components in side stream smoke are not significantly reduced in filter cigarettes when compared to non-filter counterparts. Thus, side stream smoke is a major contributor to environmental smoke, affecting both the smoker and their non-smoking counterparts, so called secondary smokers. The lower rates of consumption of cigarettes with high smoke yields has not reduced the indoor pollutants of carcinogenic substances and free radicals generating potential of tobacco smoke produced in side stream smoke, albeit their diminished levels in mainstream smoke by smoking low yield tobaccos and filter cigarettes.
Cigarette smoke induces oxidative damage to lipids, DNA and proteins, particularly protein-SH groups for this smoke contains high levels of both free radicals and aldehydes, including acetaldehyde (ethanol), propanol and acrolein, as well as other deleterious molecules.
In U.S. Pat. No. 5,060,672 (Oct. 29, 1991) which is herein incorporated by reference, Irimi and co-workers disclosed an efficient filter for tobacco smoke. Their mechanical and adsorptive filtering component also provided chemo sorptive properties to reduce aldehydes in the cigarette's smoke.
Tobacco, whether smoked as cigarettes, cigars or pipe or used as it is so-called smokeless or chewing modalities, causes common untoward effects in the oral cavity. Tobacco smoke has two chances to exert its deleterious effects in the mouth; when it is inhaled by the smoker and on its exit during exhalation. The American Lung Association states that chewing tobacco, whether one calls it snuff, a chaw, a plug, spit or smokeless tobacco is still a form of tobacco. The nicotine content is akin to cigarettes and this tobacco is etiologically responsible for oral cancer, just where it is chewed or "stored," in the mouth, cheek or gums.
Like cigarettes, evidence shows that cigars are also toxic and addictive. Cigar and cigarette smokers have a similar increased risk for oral and laryngeal cancers. While cigarette tobacco is generally flue cured with a resulting mildly acidic product, the slower curing methods for cigars render these mildly alkaline. At this pH, nicotine is more readily absorbed. Unlike cigarettes, cigars are less homogenous, and vary in size and nicotine content. Cigar smokers may spend an hour smoking a single large "Havana" although some actively inhale very little of this smoke; however, in non-inhalers, their nicotine levels may be elevated with no toxic co-absorption, as occurs in cigarette smokers. Cigar smokers also commonly hold an unlit cigar in the mouth, allowing further nicotine by local absorption. Thus, consumption of cigars may produce an equal or greater smoke burden of exposure and locally generate free radicals in the oral cavity which create deleterious effects and a risk of oro-pharyngeal disease. For cigars, as for pipe tobacco and smokeless tobacco, there is less available publicity and information for consumers than for cigarette smokers, although concomitant administration of synergistic antioxidant compositions of the present application may help prevent oral cancers and ameliorate oro-pharyngeal complications of tobacco abuse, whether from cigarettes, cigars, pipe or smokeless tobacco.
Cigarette smoke is divided into two phases, tar and gas-phase smoke. Cigarette tar contains high concentrations of free radicals. The most common oxidants include semiquinone which is in equilibrium with hydroquinones and quinones, particularly in the viscous tar matrix. Many tar extracts and the oxidants, including the latter, are water soluble and reduce oxygen to superoxide radical which can dismutate to form H.sub.2 O.sub.2. Importantly, glass-fiber type cigarette filters retain almost all of the tar particles that are larger than 0.1 micron. Thus, the filter acts as a trap for tars in cigarette smoke. There are an inordinately large number of free radicals, greater than 10.sup.15, in each puff in the gas-phase of cigarette smoke. While the oxidants in tar are stable, those organic radicals in the gas phase smoke are reactive carbon and oxygen centered radicals with extremely short half lives. Interestingly, concentrations of free radicals are maintained at high levels for more than 10 minutes and tend to increase as tobacco smoke is aged. It is thus considered that these gas phase smoke oxidants are in a steady state as they are both continuously formed and destroyed. The latter reactions are similar to those noted to occur in smog, pointing to the extra noxious stimuli to primary and secondary smokers in polluted atmospheric environments. Although the best protection from cigarette smoke oxidant damage is cessation of smoking with personal and "environmental" abstinence, antioxidant protection is rendered by oral solutions, sprays and aerosol administration, as taught by the present disclosure, and by supplemented dietary means, as suggested by some clinical investigations. These oral sprays and inhalatory measures would ameliorate and delay putative tobacco oxidant damage in smokers and their nearby non-smoking neighbors, as well as for those who use chewing (smokeless) tobaccos.
In addition to the above, in other in vitro studies gas phase cigarette smoke was assessed in its filtered and whole (unfiltered) states for oxidative effects on human plasma. Investigators noted the prevalence of lipid peroxidation in plasma after exposure to the gas-phase smoke, but not to the whole cigarette smoke. The reaction of lipid peroxidation did not commence until the endogenous ascorbic acid had been consumed, that is, vitamin C was oxidized completely. It was noted that cigarette smoke exposure caused oxidation of plasma protein thiols (methionine and cysteine amino acid linkages) and low density lipo-proteins. It was concluded that lipid peroxidation induced by the oxidants of gas phase smoke leads to changes in the lipoproteins associated with atherogenesis. As noted in this disclosure, the synergistic effect of reduced glutathione, selenomethionine and ascorbic acid or an ascorbic acid derivative are beneficial to combating tobacco oxidants and both ameliorating and delaying the effects of tobacco smoke on the oro-pharynx and the upper respiratory mucosa.
Cells subjected to oxidative stress may severely affect cellular function and cause damage to membrane lipids, to proteins, to cytoskeletal structures and to DNA. Free radical damage to DNA has been measured as formation of single-strand breaks, double-strand breaks and chromosomal aberrations. Cells exposed to ionizing radiation and cigarette smoke have also been demonstrated to have an increased intracellular DNA damage, a precursor of mutations and development of malignancies.
Macrophage cells and neutrophils have their phagocytic activity associated with the so-called "respiratory burst" reaction, which is dependent on plasma membrane NADPH oxidase activity. The resulting oxygen radicals may then be transformed to H.sub.2 O.sub.2 by superoxide dismutase. Investigators have shown that smokers have a higher "respiratory burst" reaction of alveolar macrophages and peripheral neutrophils than non-smokers and the former also have higher incidence of oral and respiratory signs and symptoms than non-smokers. It was determined that there is a decrease of the effect of this "respiratory burst" reaction in smokers supplemented with oral mega doses of antioxidants. The intra-oral and inhalatory preparations of the present invention with synergistic antioxidants are thus beneficial to primary and secondary smokers.
Because of the oro-pharynx's access to the environment, like the skin to oxygen and ultraviolet radiation, the structures of the oral cavity may be damaged by inhaled, ingested or chewed noxious substances and gaseous and particulate materials, especially in both active and passive smokers, as well as injuries by systemic xenobiotics and by endogenous processes, such as inflammatory reactions. Reactive oxidizing species, as induced by inhaled tobacco smoke, ozone and nitrous oxide are important factors in generating free radicals and inducing inflammatory reactions. As in other tissues, antioxidant enzymes exist in the oro-pharynx and include superoxide dismutase (SOD), which converts superoxide to hydrogen peroxide and catalase which reduces hydrogen peroxide to water. This reaction may also be catalyzed by selenium as a cofactor to the enzyme glutathione peroxidase using reduced glutathione (GSH) as a substrate. GSH-peroxidases may also reduce lipid peroxides to the corresponding alcohols also using GSH.
Glutathione, a sulphur containing tripeptide (L-gamma-glutamyl-l-cysteine-glycine) is the most abundant non-protein thiol in mammalian cells and is recognized as the primordial antioxidant. Glutathione, in its reduced form, known as GSH, acts as a substrate for the enzymes GSH-S-transferases and GSH peroxidases (with selenium cofactor) that both catalyze the reactions for the detoxification of xenobiotic compounds and for the antioxidation of reactive oxygen species and other free radicals. GSH synthesis takes place in two steps:
(1) An initial rate limiting step catalyzed by gamma glutamyl cysteine synthetase to form gamma glutamyl cysteine. PA1 (2) Glutathione synthetase catalyzes the reaction between glycine and glutamyl cysteine to form GSH.
Intracellular stability is conferred to GSH by the gamma glutamyl bond's resistance to intracellular peptidases. This bond may be cleaved by gamma glutamyl transpeptidase which is usually located on the external surface of cell membranes. Its activity is high in the kidney, where GSH is subject to renal clearance by tubular cells and by this transpeptidation reaction, resulting in urine excretion or retransport to plasma as the constituent amino acids, glutamine, cysteine, and glycine. In this pool, along with nutritionally derived amino acids from digestion and small bowel absorption, these amino acids are available to the liver for GSH synthesis. The liver and lung also export GSH in its oxidized form denoted as GSSG, which is produced when peroxides are detoxified by GSH peroxidase. GSSG is recycled back to the reduced form, GSH, by glutathione reductase in a reaction with NADPH.
The ubiquitous glutathione plays a vital function in maintaining the integrity of the reactive oxygen species-free radical sensitive cellular components. This is accomplished through its direct role as an antioxidant, in its reduced (GSH) form, as well as a cofactor as aforementioned. In cells, GSH concentrations for antioxidant activity are maintained in equilibrium by the enzyme glutathione reductase. Under states of GSH depletion, including malnutrition and severe oxidative stress, cells may then become injured from excess free radical damage and die.
Other non-enzymatic molecules playing an antioxidant role include the ascorbates (vitamin C) which, as free radical scavengers, also react with oxidized glutathione (GSSG) and reduce it to GSH. Also, in the lipid membrane of the cells, the hydrophobic alpha-tocopherols (vitamin E) act synergistically with vitamin C to inhibit lipid peroxidation, as may be induced by cigarette smoke, by actively scavenging lipid peroxides and other radicals.
Various studies have correlated the importance of oxidant stress to various organs resulting from tobacco smoke and other noxious environmental factors and thus continue to exert a toll on the public health of all countries. Significant morbidity and mortality result from smoking tobacco from cigarettes, cigars, and pipes and local oral pathology from chewing tobacco. Epidemiologic studies have strongly implicated tobacco in the pathogenesis of atherosclerosis and various malignancies, including oro-pharyngeal and respiratory tract neoplasias. Chronic cigarette smoking is associated with appearance of free radicals inducing oxidative damage. Measurement in blood, urine and tissues of various antioxidants or of by-products of free radical metabolic processes are supportive of tissue oxidant damage in the pathogenesis of various diseases associated with tobacco smoking and environmental pollutants.
In the oro-pharynx, cigarette smoke also accelerates the production of reactive oxygen species by recruiting local neutrophils and activation of phagocytic cells in response to the noxious agents. Attack by cigarette smoke and free radicals upon plasma proteins may be measured by carbonyl assay and by loss of enzyme activity and SH groups. Researchers have shown that whole and gas phase cigarette smoke elicit formation of carbonyl in human plasma, which is particularly inhibited by GSH. In contrast, exposure of human plasma to gas phase but not to whole cigarette smoke produces oxidative damage to lipids.
Leukoplakia, a tobacco induced white patch on the buccal mucosa, as found in smokers, is a localized irritation due to direct contact of smoked or smokeless tobacco and it is directly related to the frequency and years of tobacco abuse. Although leukoplakia is a benign oral lesion, it has a malignant potential, requiring a biopsy of the lesion to rule out cancer. Leukoplakia may regress or resolve completely when use of tobacco products is discontinued. Adequate oral examinations by primary physicians and dentists is paramount to reduce smoke induced mouth and teeth pathology.
In addition, tobacco contributes to other oral symptoms or pathologies of the mouth and teeth. Tobacco may cause halitosis, may numb the taste buds, and interfere with the smell and the taste of food. It may stain teeth and contribute to dental caries. Smokers have more dental tartar (calculus) than non-smokers. Tobacco is associated also with destructive periodontal (gum) disease and tooth loss. Acute necrotizing ulcerative gingivitis ("trench mouth") is a destructive, painful inflammatory condition occurring mainly in cigarette smokers. Swelling of the nasal and sinus membranes have also been associated, purportedly, in individuals who are "allergic" to tobacco smoke.
Besides leukoplakia, another generalized whitish hue on the buccal mucosa represents the entity of oral submucous fibrosis. This disease occurs mainly in India and is a chronic, progressive premalignant condition. The etiology is chronic chewing of tobacco or areca nut or both. The fibrosis results in restriction of mouth opening and involves the palates, tonsillar fossa, buccal mucosa and underlying muscle. Associated with this condition is also oro-pharyngeal carcinomas, also with a high frequency in India and associated in 70% of cases with chewing tobacco. Smokeless tobacco and areca nut usage is also common in Pakistan, Bangladesh and Java and in these and Indian immigrants to the United States and United Kingdom.
Over 30,000 new cases of cancer of the oral cavity are diagnosed annually, accounting for two to four percent of all new cancers. Oral cancer kills 8,000 patients each year and only half of cases diagnosed annually have a five year survival. The great majority of these patients are users of tobacco products. Other risk factors include alcohol abuse, nutritional deficiencies and poor oral hygiene.
Research has recently linked benzopyrene, as in cigarette smoke, with mutations to the human P53 gene leading to oral and respiratory malignancies. Notably, 3, 4-benzopyrene is present in polluted atmospheres of large cities such as Los Angeles, Mexico City, and London, emanating as an exhaust product of motor traffic, especially diesel engines. Breathing contaminated air with high concentrations of this compound, particularly under foggy conditions as in London, provides more than 100 times as much of this putative mutagen than for a heavy cigarette smoker. Thus, the use of the present invention as taught herein would be most beneficial to citizens, particularly if they are also smokers, of congested cities with much traffic and with smog and fog. This provides to the individual another protective measure to such free radicals and mutagens generated in their bodies, not withstanding important measures to decontaminate the atmospheric pollutants and public health and personal efforts at tobacco cessation.
Cigarette filters "trap" nicotine tars but not the gas phase compounds. Epidemiologic studies have been done in various countries to show the differential effects of tar content, amount of cigarettes smoked, type of tobacco smoked, and use of filters on oro-pharyngeal and pulmonary cancer risk in cigarette smokers.
Cigarette smoke has untold effects through free radicals and other mechanisms of affecting other organs, such as the skin. Dr. Douglas Model of England in 1985 added to the medical lexicon the term "smoker's face" from a study with pictures of 116 cases and suitable non-smoking controls. Akin to photodamage, those with smoker's face appear older and have more wrinkles. They also have a greater frequency of cancers of the lips and mouth.
Recently, sales of cigars have risen, partly due to their gaining popularity with women and the advent of the female friendly "cigar bar." Evidence, however, exists that cigar carcinogenic particles exceed those of three cigarettes and the level of carbon monoxide is 30 times greater. Fumes from cigars are of greater consequence to secondary smokers. Epidemiologic studies reveal greater frequencies of heart disease, emphysema, and cancers of the mouth and pharynx in cigar smokers when compared to matched non-smokers.
There are a number of preparations on the market as dentifrices, gels, breath fresheners and mouthwashes and oral rinses to protect the mouth and teeth from the effects of chewed or smoked tobacco. Cigarette tar may deposit on the teeth, gums, tongue and other surfaces of the oral cavity of smokers. Tobacco tar, a dark, oily, viscid blend of polycyclic aromatic and aliphatic hydrocarbons, is produced in cigarettes, cigars, or pipe smoke by the burning of the tobacco. The smoker inhales the tar and other tobacco smoke combustion products are sucked into the oral cavity and respiratory passages. The smoke is then exhaled, passing a second time through the mouth of the smoker, anew depositing tar. This causes discoloration of the teeth and other oral surfaces. Not only may there be smoker's "bad breath" but also tooth decay and gum disease. Smokeless tobacco is equally locally deleterious. Food particles, oils and other substances may also be deposited on mouth surfaces. The tars and mainstream smoke will elicit free radical and inflammatory responses in the mouth and other mucosal surfaces. The antioxidants and reparative preparations of this invention may be prepared as oral and dental compositions as well as with optional added ingredients that are also breath fresheners, fluorides, anti-microbials, and solubilizers of tars and essential oils. Most of the dental products used as "anti-tobacco" are in the form of toothpastes and gels.
Diamond patented a combination of non-ionic and anionic surfactants with at least one essential oil as dental and oral preparations for smokers for solubilizing and removing tobacco tars as well as onion and garlic essential oils. U.S. Pat. No. 5,514,366 (May 7, 1996), herein incorporated by reference, teaches complimentary uses of the preventive and reparative effects of the present invention.
GSH has been shown to have multiple functions in detoxification and its depletion in extracellular fluids and cells is associated with an increased risk of chemical toxicity. Although there are large variations in dietary sulphur amino acid content, these variations do not correlate with GSH levels in the blood plasma pool. These GSH levels, however, do vary with age, race and gender of human subject and with dietary habits and intakes. Investigators have reported that extracellular pools of GSH, including plasma, respiratory tract lining fluid and oral and small intestinal lumen are GSH vital protectants against chemically induced injury. These would include the chemicals in tobacco smoke and other environmental pollutants as well as chemicals in smokeless tobacco preparations and other chewable or orally ingested substances. The aforementioned pools, through GSH and related synergistic antioxidants, as proposed in the present invention, detoxify chemicals extracellularly, supply GSH and its precursor amino acids to cells and protect the extracellular surface of the plasma membrane from damage. Alterations in GSH status could thus alter this regulatory function by GSH and thereby lower the threshold for chemically induced cell death by apoptosis, making GSH both a useful protectant to and biomarker for risk from a variety of single or mixtures of deleterious chemicals, such as in various types of tobacco.
Some mammalian cells are able to absorb intact the tripeptide glutathione. It may also be synthesized by some organs, particularly the liver. Various scientific papers have addressed a method for proper replacement of glutathione, particularly to increase cellular levels in glutathione depleted states. Certain diseases cause glutathione depletion from interaction endogenously with metabolic intermediates, the various deleterious free radical species. Labeling glutathione, at the intracellular level as the "antidote physiologically appointed to the neutralization and thus detoxification, by the formation of covalent bonds, of highly reactive toxic substances of endogenous or exogenous origin," Pilotto and coworkers patented dipeptide compounds with pharmaceutical properties to replete the body's glutathione levels. Their U.S. Pat. No. 4,761,399 dated Aug. 2, 1988, teaches raising glutathione levels by various routes, including oral, inhalation and parenteral methodologies. Meister, in U.S. Pat. No. 4,710,489 issued Dec. 1, 1987 teaches new molecules to increase cellular levels of glutathione. The invention of the '489 patent deals with using pure alkyl mono-esters of glutathione, wherein the ester is a glycine carboxylic acid. These molecules may be administered orally or by injection.
It is thus an object of the present invention to provide various compositions and methods of employing such compositions for preventing and ameliorating signs and symptoms and complications to the oro-pharyngeal cavity and mouth including buccal mucosa, gums, teeth and tongue as well as the upper respiratory tract as a result of tobacco oxidants and other gaseous and particulate matter pollutants.
These and further objects will be more readily appreciated when considering the following disclosure and appended claims.